A unit that smells of solvent when the box is opened gets returned, however well it works.
Buyers evaluate a sample on a desk. Users open the box at home, and the first thing they notice is the smell.
1. The sample and the shipment are not the same thing
A sample is usually produced weeks before the bulk order, and it has time to air out.
Bulk units arrive sealed and fresh from the line, and the smell has not gone anywhere.
The trap: the sample smelled acceptable, so the odour question is assumed to be closed. Nobody rechecks it at the moment the customer actually opens the box.
2. Where the smell comes from
It comes from materials, not from the electronics.
Most of it is residual solvent and unreacted compounds that have not finished curing. Foam, coated fabric and printed packaging all contribute.
Volatile organic compounds - VOC - is the general term for these emissions. The number that matters is the emission after a defined curing period, not the smell on the day of production.
The trap: odour is assessed either on the day the sample is finished, when it is strongest, or weeks later, when it has faded. Neither matches the condition the customer receives.
3. The three materials that cause most of it
Memory foam. Freshly poured foam releases blowing agents and residual monomers. Density and curing time both change how much.
PU and neoprene fabric. Coating solvents need time to flash off, and lower grades need longer.
Printed packaging and the insert. Ink and adhesive are the most overlooked sources, because nobody thinks of the box as a source of smell.
The trap: the foam is changed, the smell remains, and it turns out to have been the insert all along.
4. How to set a limit that can be tested
Write the odour requirement with a method, not an adjective.
"Low odour" cannot be tested. "No objectionable odour after 72 hours in a sealed bag at room temperature" can be, and a third party can repeat it.
The trap: the requirement is written as "no smell", and every shipment fails it in somebody's judgement.
5. What belongs in the specification
Curing time before packing, stated in hours
Packaging material type, and whether it is printed
A defined odour test: sealed bag, temperature, duration
Whether bulk units are bagged or vented before cartoning
Settle these four lines and most odour complaints disappear before the container leaves. Look through our health massager range or contact us and we will confirm which of the four are already set for your product.
